Hydrocarbon-producing wells commonly consist of a wellbore extending through a subterranean formation and lined with a tubular casing. Cement is pumped into an annulus between the wellbore and the casing to fix the casing within the wellbore. Once the casing is cemented in place, a perforating gun is lowered to depth within the casing and fired to create one or more perforations extending through the casing and cement and into the surrounding formation. The perforations generally permit communication of fluid between the internal volume of the casing and the surrounding formation.
Once perforated, wells are often stimulated using various stimulation treatments to improve production. In hydraulic fracturing treatments, for example, a viscous fracturing fluid is pumped into a perforated production zone at sufficiently high pressure to create fractures within the production zone and to propagate existing or newly created fractures. The fractures improve production by providing new or enhancing existing pathways for fluid to move between the formation into the casing.
An acidizing is another example of a treatment that may be performed on a wellbore. Acidizing treatments involve the introduction of an acid or similar fluid into the formation. The acid dissolves debris introduced into the formation during perforation and fracturing. Acidizing may also be used to improve permeability of the formation by partially dissolving the formation, enlarging existing fluid pathways.
A well may include multiple production zones, with each production zone requiring its own perforation and treatment. Production zones are typically perforated and treated beginning with the farthest downhole production zone and proceeding sequentially uphole. To properly treat an uphole production zone, an operator may need to isolate the uphole production zone from downhole production zones that have been previously perforated and treated. For example, in fracturing treatments, isolating an uphole production zone to be fractured from a downhole production zone that has already been fractured enables more efficient build-up of pressure within the production zone to be fractured because fracturing fluid is not lost to the formation via the previously fractured production zone. Isolation in the fracturing context may also protect the previously fractured production zone from additional, unwanted fracturing.
Given the prevalence of stimulation treatments, there is a consistent drive among operators to lower costs and improve efficiencies associated with completion and fracturing operations.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.